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  <title>Checks if attribute is a defined ID</title>

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</div><hr /><div id="domattr.isid" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">DOMAttr::isId</h1>
  <p class="verinfo">(PHP 5)</p><p class="refpurpose"><span class="refname">DOMAttr::isId</span> &mdash; <span class="dc-title">
   Checks if attribute is a defined ID
  </span></p>

 </div>
 <div class="refsect1 description" id="refsect1-domattr.isid-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><strong>DOMAttr::isId</strong></span>
    ( <span class="methodparam">void</span>
   )</div>

  <p class="para rdfs-comment">
   This function checks if the attribute is a defined ID.
  </p>
  <p class="para">
   According to the DOM standard this requires a DTD which defines the 
   attribute ID to be of type ID. You need to validate your document with
   <a href="domdocument.validate.html" class="xref">DOMDocument::validate</a> 
   or <em>DOMDocument::validateOnParse</em> before using this function.
  </p>
 </div>

 <div class="refsect1 returnvalues" id="refsect1-domattr.isid-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   成功时返回 <strong><code>TRUE</code></strong>， 或者在失败时返回 <strong><code>FALSE</code></strong>。
  </p>
 </div>

 <div class="refsect1 examples" id="refsect1-domattr.isid-examples">
  <h3 class="title">范例</h3>
  <p class="para">
   <div class="example" id="example-5276">
    <p><strong>Example #1 DOMAttr::isId() Example</strong></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /><br />$doc&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">DomDocument</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">//&nbsp;We&nbsp;need&nbsp;to&nbsp;validate&nbsp;our&nbsp;document&nbsp;before&nbsp;refering&nbsp;to&nbsp;the&nbsp;id<br /></span><span style="color: #0000BB">$doc</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">validateOnParse&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">true</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$doc</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">Load</span><span style="color: #007700">(</span><span style="color: #DD0000">'book.xml'</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">//&nbsp;We&nbsp;retrieve&nbsp;the&nbsp;attribute&nbsp;named&nbsp;id&nbsp;of&nbsp;the&nbsp;chapter&nbsp;element<br /></span><span style="color: #0000BB">$attr&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$doc</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">getElementsByTagName</span><span style="color: #007700">(</span><span style="color: #DD0000">'chapter'</span><span style="color: #007700">)-&gt;</span><span style="color: #0000BB">item</span><span style="color: #007700">(</span><span style="color: #0000BB">0</span><span style="color: #007700">)-&gt;</span><span style="color: #0000BB">getAttributeNode</span><span style="color: #007700">(</span><span style="color: #DD0000">'id'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$attr</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">isId</span><span style="color: #007700">());&nbsp;</span><span style="color: #FF8000">//&nbsp;bool(true)<br /><br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

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  </p>
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